CHROMIUM: mwifiex: make use of bgscan flag provided in scan request

CHROMIUM: mwifiex: make use of bgscan flag provided in scan request

This new flag indicates scan type. We will cancel/abort scan
operation based on traffic only for background scan. Foreground
scan will have higher priority. Hence it will never be cancelled
or aborted.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
BUG=chrome-os-partner:13861
TEST=Build and run autotest suites

Change-Id: I465c337def80d5ec2cae3567167d718bc3b2ff7e
Reviewed-on: https://gerrit.chromium.org/gerrit/33852
Reviewed-by: Gary Morain <gmorain@chromium.org>
Tested-by: Bing Zhao <bzhao@marvell.com>
Commit-Ready: Bing Zhao <bzhao@marvell.com>